BANGOR, Maine — The child pornography case against a former assistant attorney general could go to trial in U.S. District Court as early as next month after a federal judge Tuesday dismissed three pending motions, which claimed the charges were based on politics not evidence.

James Cameron, 46, formerly of Hallowell, pleaded not guilty in February to 16 counts of transporting, receiving and possessing child pornography between July 10, 2006, and Jan. 26, 2008.

Cameron worked for the Maine Attorney General’s Office and was the state’s top drug prosecutor until he was fired in April 2008.

In a strongly worded 13-page order, U.S. District Judge John Woodcock said that the “claims of vindictive and selective prosecution are unfounded, are contradicted by the evidence in this record, and do not generate the right to further discovery.”

Cameron’s attorney, Peter Rodway of Portland, filed a handful of motions including one seeking to suppress the evidence and another claiming that the prosecution of his client was vindictive and selective because of political difference between the Maine Attorney General’s Office and the U.S. Attorney’s Office. He also alleged the charges were filed as a result of prosecutorial discretion, buckling to institutional pressure and personal animus rather than the evidence.

Rodway argued in his motions that the charges against his client were the result of disputes between U.S. Attorney Paula Silsby, who was appointed by President George W. Bush, and former Maine Attorney General Steven Rowe, who has announced he is running for the 2010 Democratic nomination for governor.

Efforts to reach Rodway on Wednesday were unsuccessful.

On Tuesday, the judge found “the notion that Ms. Silsby sought to discredit Mr. Rowe by prosecuting his close Democratic advisor is patently fanciful, since it was Mr. Rowe himself who made the referral to the United States Attorney. Further, to demonstrate that he has been prosecuted because he was a Democrat, Mr. Cameron would have to demonstrate that there have been Republicans engaging in similar conduct, who have not been prosecuted.”

Woodcock also was appointed by President George W. Bush.

The investigation and indictment, the judge wrote, were triggered by reports from Yahoo! an Internet service provider, to the National Center for Missing and Exploited Children that numerous images of child pornography had been identified in an account registered to Cameron’s wife, Barbara Cameron. Evidence that led investigators to James Cameron included a profile under the name Jim and a user description that fit the former attorney general — a married, 45-year-old man with a daughter, Woodcock said.

Rowe turned the case over to Silsby’s office in January 2008 and Cameron was indicted 13 months later.

“The decision to take the case federally is not,” Woodcock wrote, “evidence of selective or vindictive prosecution; rather, it is consistent with sensible prosecutorial practice on the part of both sate and federal prosecutors.”

Earlier this month, Woodcock denied Rodway’s motion to suppress. The judge ruled that prosecutors may use evidence seized from Cameron’s computers. Rodway claimed, according to a previously published article, that the scope of the search warrant was too broad and the search of the files was performed long after the warrant had expired.

Cameron allegedly uploaded images of child pornography to an Internet-based Yahoo photo album using five different screen names. Cameron, according to the indictment, also transmitted digital images of child pornography using Google Hello, an Internet-based chat and file-sharing service.

The images of child pornography allegedly were found on Cameron’s home computers. His work computer was seized but no images were found on it, Rodway said after his client’s arraignment.

If convicted, Cameron faces a minimum of five years but not more than 20 years in federal prison and a fine of up to $250,000.

Cameron remains free on $75,000 unsecured bail and is living with his brother Daniel Cameron in Westland, Mich. Bail conditions include wearing an electronic monitor and limited use of the Internet.

Jury selection in his trial is tentatively set to begin on Oct. 5.

It would not be unusual for the trial to be continued until after the first of the year.